BSC 212 Exam 3

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84 Terms

1
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what is a fruit?

the matured ovary, often accompanied by accessory tissue which clings to the ovary when matured

2
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what is a seed?

matured embryo, stored food, protective seed coat

3
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what is embryogenesis?

formation of the embryo, establishes a body plan for the plant

4
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how does the apical cell divide?

many times to become the embryo proper

5
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what does the basal cell become?

the suspensor

6
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what is the cotyledon?

embryonic leaf, first leaves to appear when seeds germinate

7
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what does germination depend on?

water, oxygen, temp, light, seed coat rigidity, embryo dormancy by abscisic acid & gibberellic acid

8
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what occurs during germination?

-primary root emerges
-epigeous or hypogeous stem emerges based on species

9
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what is the epigeous stem?

cotyledons are carried out of the ground

10
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what is the hypogenous stem?

cotyledons remain underground

11
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what are breeding systems?

methods by which plant reproduce sexually

12
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what are the 2 types of reproduction?

1) asexual
2) sexual

13
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what is asexual reproduction?

vegetative (mitosis) the stolon & rhizomes

14
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what is sexual reproduction?

alteration of meiosis & fertilization
-selfing
-outcrossing

15
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what are the pros of asexual reproduction?

-reproduce quickly
-facilitate survival when difficult to find mates

16
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what are the cons of asexual reproduction?

-deleterious genes do major damage
-genetically constrained

17
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what are the pros of sexual reproduction?

-faster to obtain new favorable mutations (recombination during meiosis)
-novel genotypes: mating with populations & migration
-red queen hypothesis: host populations are continually evolving in response to pathogens
-avoiding mueller's ratchet: accumulation of deleterious mutation (via genetic recombination w/ natural selection)

18
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what are the cons of sexual reproduction?

costly process

19
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what are deleterious genes?

detrimental sequence of nucleotides forming the chromosome

20
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what is a monoecious plant?

male & female organs on one plant (hermaphroditic)

21
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what is a dioecious plant?

plants with male organs & plants with female organs

22
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what is a gynodioecious plant?

plants with female organs & plants with male and female organs

23
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what is a androdiecious plant?

plants with male organs & plants with male and female organs

24
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what are the 3 drivers that affect the frequency of female plants in a population?

1) genetic drift: greater unpredictability in female frequency
2) nutrients in soil: more nutrients, more females
3) soil microbial community

25
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what is chasmogamous?

open flowers

26
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what is cleistogamous?

closed flowers, must self-pollinate

27
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what is a protandrous plant?

male organs come to maturity before the female

28
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what is a protogynous plant?

female organs come to maturity before the male

29
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what is self-incompatibility?

inability to produce zygotes after self-pollination in a fertile hermaphrodite plant

30
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how does SI work?

-sporophytic self incompatibility (SSI)
-gametophytic self-incompatibility (GSI): more common (60-90 families), less understood

31
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what is gametophytic self-incompatibility (GSI)?

pollen exhibits incompatibility phenotype determined by its gametophytic genome (pollen): "like-matches-like inhibition"

32
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what is sporophytic self-incompatibility?

pollen exhibits incompatibility phenotype of the sporophyte (diploid) parent (the female): "any-match-inhibition"

33
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what are heteromorphic flowers?

perfect flowers with different structures

34
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what is heterostyly?

different length relative to stamen in the flowers to reduce self-fertilization

35
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what is distyly?

stamen & style 2 different heights

36
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what is tristyley?

stamen & style 3 different heights

37
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what is evolution?

change in characteristics of organisms over many generations

-takes place over generations, can be rapid

-changes must be hereditary

-selection is the mechanism of evolution

38
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what are adaptations?

changes that better suit an organism to its environment

-arise from mutations selected on

-occur over generations, assimilations is change in individual

-NOT intentional

39
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what is a species?

group that can interbreed but cannot with other groups
-speciation
-genetic isolation, restricts gene flow

40
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what are mutations?

heritable changes in the genotype, most occur spontaneously

41
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what is fitness?

viable offspring averaged over similar individuals & divided by average for all individuals in the population

42
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what is the founder effect?

small population is separated & has a different gene pool than the parent

43
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what is the bottleneck effect?

population is drastically reduced by an event (not selection) & the gene pool is disrupted

44
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what is gene flow?

movement of alleles into or out of a population
-movement of gametes by pollen between pop.
-wind plants pollen falls around 50m

45
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what does gene flow depend on?

proximity, wind patterns, pollinators, phenology

46
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what is genetic drift?

change in gene pool due to chance

47
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what can genetic drift lead to?

1) speciation: creation of a new species
2) inbreeding: breeding among closely related individuals

48
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how is genetic drift calculated?

by measuring the effective population size (N left) or genetically unique individuals

49
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what is inbreeding depression?

reduced fitness due to increased homozygosity; closely related individuals breeding

50
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when is speciation & inbreeding more likely to happen?

when the gene pool is reduced, less variability (more similar genetically)

51
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what is sympatric speciation?

polyploids (2+ sets of chromosomes), chromosomes do not separate during meiosis, diploid gametes created, diploid gametes combine

52
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what is the result of sympatric speciation?

-hybrid cannot undergo meiosis because chromosomes cannot pair
-autopolyploidy double the chromosomes then after meiosis

53
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what are bryophytes?

earliest land plants:
-liverworts
-mosses
-hornworts

54
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what are ferns?

seedless vascular plants

55
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what are gymnosperms?

plants that produce seeds without flowers:
-conifers
-cycads
-gingko
-gnetophytes

56
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what are angiosperms?

plants that produce flowers as reproductive organs

57
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what is paleobotany?

study of ancient plants with fossils

58
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what does green algae have in common with vascular plants & bryophytes?

-contain chlorophylls a & b
-store starch inside plastids
-some have firm cell walls w/ cellulose, hemicellulose, pectin
-flagellated reproductive cells
-alternation of heteromorphic generations

59
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what is the alternation of heteromorphic generations?

one generation is diploid (2n) & one generation is haploid (n)
key features:
-meiosis
-fertilization
-gametophyte (n)
-sporophyte (2n)
occurs in nonvascular plants

60
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what are lichen (not plants)?

symbiotic partnership between fungus & alga:
fungus for decomposition, algae partner (green algae or cyanobacteria) for photosynthesis

61
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mosses reproductive cycle:

1) spores released
2) spores germinate
3) gametophytes form
4) sperm to egg = zygote
5) zygote divides = sporophyte
6) venter forms calyptra
7) meiosis in capsule = haploid spores

62
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what is heterospory?

production of 2 types of spores in 2 different sporangia

63
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what does is mean to be homosporous?

meiosis produces only 1 kind of spore (many ferns)

64
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what are oogamous plants?

vascular plants, nonmotile, large egg with sperm that swims to eggs
-sporophyte more complex than gametophyte

65
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fern reproductive cycle:

1) spore made in the sporangia
2) spores dispersed
3) heart-shaped gametophytes with rhizoids
4) achegonia (F) & antheridia (M) sex organs on single gametophyte
5) sperm released by water fertilize neighboring egg
6) zygote to embryo to sporophyte

66
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what is the dominant generation in the fern reproductive cycle?

sporophyte
(generations independent)

67
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how do fern seeds disperse?

water

68
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what are the limitations to spores in ferns?

megaspores released
limited nutrition available

69
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what are the limitations to free-living gametophytes in ferns?

-genetically sensitive to mutations since 1N
-small limited support for embryo & young sporophyte

70
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what is the best potential source for support (nutrition & protection) in ferns?

-need to have dimorphic spores
-retain megaspores
-retain female gametophytes
-sperm needs to be able to get to the ovule

71
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when did farming practices arise?

10,000-1000 years ago
(neolithic revolution)

72
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primitive agriculture:

-domestication of plants
-new tools & pottery
-plows: increased nutrient availability to plants
-manure as fertilizer
-harnessed animals

73
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farming in the 1700s-1800s:

foundations of industrial ag:
-more machinery, still powered by animals
-steam engines
-mendel & plant genetics (1865)
-railroads (1869)
-first combine harvester (1884)
-beginning of seed businesses (1890s)

74
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conventional farming: 1900s-current

-efforts to feed growing population
-haber-bosch process developed (1913)
-horses replaced with machines (tractors: 1915)

75
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tracking farming trends of 1850-1940s:

-# of farms growing
-farm size relatively small, less than 200 acres

76
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tracking farming trends of 1940s-current

-# of farms shrinking, fewer farms
-large-scale farms, now some 4.64 acres

77
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1940-2000s farming:

-era of genetics, biochem, large scale farming
-industrialization: cheaper food, dependence on agrochemicals & fuel

78
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21st century farming:

-advanced genomics & sustainability movement
-plant genome, new concepts for pests, computerized data, consideration of climate change

79
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when did organic farming practices arise?

1930s-late 1940s: followed the Dust Bowl (1930-1940) & concerns for healthy soil

80
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long-term agricultural studies:

-Rothemstead, England: (1843) to present for Ag studies
-The Park Grass experiment (1856): fertilizers affect on hay - longest ecological experiment in the world
-The Morrow Plots: (1876) for understanding crop rotation, soil nutrient depletion & fertilizers

81
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what are some attributes for organic farming?

-sustainable considerations for farming (1900s) in response to observed damages due to pesticides/fertilizers
-no use of pesticides, herbicides, synthetic fertilizers
-no use of GMOs
-must protect their products for coming in contact with all of the above

82
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what are some attributes for conventional farming?

-chemical intervention for pests (pesticides) & weeds (herbicides)
-providing fertilizers
-does not have to mean monocropping

83
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what is food insecurity?

lack of available food and/or lack of resources to buy or barter for it
-800 mil (11%) of global pop in 2018
-US: 12.8% of households in 2022, 34 mil people

84
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what are the risks to food insecurity?

-low wages
-unemployment
-insufficient social safety net for those w/ no or low income (single-parent families)
-living in rural area
-gov. & private industries that do not provide resources & aid to farmers
-lack of edu.
-environmental degradation